Insecticidal (β-phenyl-β-substituted-vinyl)cyclopropanecarboxylates

ABSTRACT

New insecticidal (β-phenyl-β-substituted-vinyl)cyclopropanecarboxylates in which the β-substituent may be halogen or lower haloalkyl are described and their preparation and insecticidal utility are exemplified.

This is a continuation-in-part of copending application Ser. No. 718,252filed Aug. 27, 1976, now abandoned.

This invention relates to the general field of insecticides,particularly to insecticides for use in agriculture to protect crops andanimals, but also for household and insecticidal use. The activecompounds of this invention are insecticidal esters of2,2-dimethyl-3-(β-phenyl-β-substituted-vinyl)cyclopropanecarboxylicacid.

Ever since the structures of naturally occurring pyrethroids wereelucidated, synthesis efforts have been directed toward the preparationof related compounds of enhanced insecticidal activity and improvedstability toward air and light. A noteworthy advance in this area wasthe discovery by Elliott et al of certain highly active compoundsremarkably resistant to photooxidative degradation, for example,3-phenoxybenzyl3-(β,β-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate, Nature, 246,169 (1973), Belgian Pat. Nos. 800,006 and 818,811.

Despite the extensive activity in the field of insecticidalcyclopropanecarboxylates, insecticidal2,2-dimethyl-3-(β-phenyl-β-substituted-vinyl)cyclopropanecarboxylateshave not been described prior to the present invention.

The compounds of the present invention have the formula: ##STR1## inwhich X is halogen, such as fluoro, chloro, or bromo, cyano, nitro,aryl, such as phenyl, thienyl, furyl, or pyridyl, aralkyl, such asbenzyl, lower alkyl, lower haloalkyl, lower alkoxy, lower alkylthio,aryloxy, arylthio, di-(lower alkyl) amino, or methylenedioxy; Y ishalogen, for example chloro, bromo, or fluoro, preferably chloro orlower haloalkyl; n is 0, 1, 2, or 3, more commonly 0, 1, or 2; and R isthe residue of an alcohol which in combination with an appropriate acidmoiety yields an insecticidal cyclopropanecarboxylate. A wide range ofsuch alcohols are known to the insecticide art. Those R groups useful incompounds of the present invention include:

(1) a benzyl- or phenoxy-substituted benzyl group of the formula:##STR2## wherein Z is hydrogen, methyl, cyano, ethynyl, or phenyl, and Ais --O-- or --CH₂ --;

(2) a benzyl- or phenoxy-substituted furylmethyl group such as5-benzyl-3-furylmethyl;

(3) an imidomethyl group such as maleimidomethyl, phthalimidomethyl, andtetrahydrophthalimidomethyl;

(4) a benzyl group substituted in at least two ring positions withchloro, methyl, or methylenedioxy groups, for example3,4-methylenedioxybenzyl, 2-chloro-4,5-methylenedioxybenzyl, and2,4-dimethylbenzyl;

(5) a substituted cyclopentenonyl group such as allethrolonyl.

The more readily available R groups which give active insecticides ofthe present invention are 3-phenoxybenzyl, α-cyano-3-phenoxybenzyl, and5-benzyl-3-furylmethyl.

In the substituents X and Y, lower means having one to four carbonatoms, preferably, and particularly for the haloalkyl and aminosubstituents, having one or two carbon atoms. Examples of halomethylsubstituents include trichloromethyl and trifluoromethyl groups.

The preparation and insecticidal properties of the compounds of thisinvention are illustrated in the following specific examples. Unlessotherwise specified, all temperatures are in degrees centigrade, andconcentration of liquid volume was carried out under the reducedpressure produced by a water aspirator.

EXAMPLE 1 Synthesis of3-(β-Chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarbonyl Chloride

A. Preparation of Ethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate

To a solution of 28.35 g of diethyl benzylphosphonate in tetrahydrofuranat -78° was added one equivalent of n-butyllithium in hexane. After thereaction mixture was stirred at -70° for 40 minutes, 124 ml of carbontetrachloride was added. The mixture was stirred for an additional 40minutes at -70°, then 23.6 g of caronaldehyde was added. The mixture wasallowed to warm to room temperature, and 27 ml of water was then added.The reaction mixture was extracted with diethyl ether. The etherealextract was concentrated, treated with 200 ml of pentane at -50°,triturated, and the pentane decanted. The residue was treated with 200ml of pentane at -30°, triturated, and the pentane decanted. Thecombined decantates were concentrated to an oil, which was treated with19 g of sodium bisulfite in 50 ml of water. The mixture was extractedwith 50 ml of diethyl ether. The extract was washed with 50 ml ofsaturated aqueous sodium chloride solution, dried over anhydrousmagnesium sulfate, and concentrated to yield 19.71 g of oil. The oil waspurified by chromatography on 98.5 g of silica gel, with 95:5hexane:ether as eluent. The solvents were removed under reduced pressureto yield 14.4 g of ethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate as amixture of isomers containing cis, trans, (E), and (Z) forms. The nmrand ir spectra were consistent with the assigned structure.

B. Preparation of3-(β-chloro-β-phenylvinyl)-2,2-dimethylcycloproanecarboxylic acid

A mixture of 16.91 g of ethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate, 2.57 gof sodium hydroxide, 4.6 ml of water, and 72 ml of ethanol was heated at55° for 17 hours. The mixture was allowed to cool and was concentratedto near dryness. A saturated aqueous sodium chloride solution was addedto the concentrate and the mixture thus formed was washed withchloroform. The aqueous phase was acidified with 3% hydrochloric acidand extracted with diethyl ether. The ethereal extract was concentratedto yield approximately 14.57 g of3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylic acid. Thenmr and ir spectra were consistent with the assigned structure.

C. Preparation of3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarbonyl chloride

A 14.57 g portion of3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylic acid wasdried by twice azeotropically distilling the contained water withbenzene. The acid was then diluted with 52 ml of benzene, and 9 ml ofthionyl chloride was added to the solution. The mixture was heated underreflux for 3 hours. The excess thionyl chloride was removed bydistillation. More benzene was added, and further distillation removedall traces of thionyl chloride. The reaction mixture was diluted to avolume of 100 ml with benzene. One third of this solution was used forthe preparation of each of three esters described below.

EXAMPLE 2 Synthesis of 3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate

A 33.3 ml portion of the3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarbonyl chloridesolution in benzene of Example 1C was added at 0° C. to a stirredsolution of 4.0 g of 3-phenoxybenzyl alcohol and 4 ml of pyridine in 26ml of benzene. The reaction mixture was stirred at ambient temperaturefor 14 hours. The pyridine hydrochloride was removed by filtration. Thefiltrate was evaporated under reduced pressure to give 8.6 g of residualoil. The residual oil was purified on a chromatographic column of 42.5 gsilica gel. Elution was accomplished with 860 ml of 20% methylenechloride/80% pentane to give 6.41 g (77%) of 3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate.

Analysis: Calc'd for C₂₇ H₂₅ ClO₃ : C, 74.90; H, 5.82; Found: C, 74.81;H, 5.83.

EXAMPLE 3 Synthesis of 5-benzyl-3-furylmethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate

This compound was prepared by the method of Example 2, with 33.3 ml ofthe 3-β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarbonylchloride/benzene solution, 3.75 g of 5-benzyl-3-furylmethyl alcohol and4 ml of pyridine in 26 ml of benzene. The yield was 6.14 g (46%) of5-benzyl-3-furylmethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate.

Analysis: Calc'd for C₂₆ H₂₅ ClO₃ : C, 74.19; H, 5.99; Found: C, 74.10;H, 6.03.

EXAMPLE 4 Synthesis of α-cyano-3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate

This compound was prepared by the method of Example 2, with 33.3 ml ofthe 3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarbonylchloride/benzene solution, 4.50 g of α-cyano-3-phenoxybenzyl alcohol and4 ml of pyridine in 26 ml of benzene. The yield was 7.12 g (81%) ofα-cyano-3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate.

Analysis: Calc'd for C₂₈ H₂₄ ClNO₃ : C, 73.43; H, 5.28; N, 3.06; Found:C, 73.60; H, 5.31; N, 3.08.

EXAMPLE 5 Toxicity to Insects and Mites

Initial Contact Activity

One quarter gram of test compound was dissolved in 20 ml of acetone andthis solution was dispersed in 180 ml of water containing one drop ofisooctylphenyl polyethoxyethanol. Aliquots of this solution, whichcorresponds to 1250 ppm of active ingredient, were diluted with anappropriate amount of water to provide solutions containing the reportedconcentration of active ingredient. Test organisms and techniques wereas follows: the activities against the Mexican bean beetle (Epilachnavarivestis Muls.) and the southern armyworm (Spodoptera eridania[Cram.]) were evaluated by dipping the leaves of pinto bean plants intothe test solution and infesting the leaves with the appropriateimmature-form insects when the foliage had dried; the activity againstthe pea aphid (Acyrthosiphon pisum [Harris]) was evaluated on broad beanplants whose leaves were dipped before infestation with adult aphids;the activity against two-spotted spider mites (Tetranychus urticae Koch)was evaluated on pinto bean plants whose leaves were dipped afterinfestation with adult mites; the activity against the milkweed bug(Oncopeltus fasciatus [Dallas]) and the boll weevil (Anthonomus grandisBoheman) were evaluated by spraying the test solutions into glass dishesor jars containing the adult insects. All organisms in the test weremaintained in a holding room at 80° F. and 50% relative humidity for anexposure period of 48 hours. At the end of this time, the dead andliving insects or mites were counted, and the percent kill wascalculated. Results of these tests are summarized in Table 1.

Residual Contact Activity

The residual contact activity of the compounds was determined on thesame organisms using the techniques described above, except that in eachcase the treated surface was allowed to dry and was exposed to normallight and air for seven days before introduction of the mites orinsects. Results of these tests are summarized in Table 2.

EXAMPLE 6 Comparative Tests for Initial Contact Activity

For the purpose of demonstrating relative initial contact insecticidalefficacy, the compounds of Examples 2 and 4 were compared with theallethrolonyl, 3-phenoxybenzyl, and α-cyano-3-phenoxybenzyl esters of3-(β,β-diphenylvinyl)-2,2-dimethylcyclopropanecarboxylic acid, referredto in Table 3 as compounds A, B, and C respectively. The compounds weretested in accordance with the procedures set forth in Example 5,Toxicity to Insects and Mites, Initial Contact Activity. The datareported in Table 3 show the claimed compounds to be vastly superior ininsecticidal and miticidal efficacy to compounds A, B, and C.

It is anticipated that, in the normal use of the compounds of thepresent invention as insecticides, the compounds will usually not beemployed free from admixture or dilution, but will ordinarily be used ina suitable formulated state compatible with the method of application.The insecticidal cyclopropanecarboxylates of this invention may beformulated with the usual additives and extenders used in thepreparation of pesticidal compositions. The toxicants of this invention,like most pesticidal agents, are incorporated with the adjuvants andcarriers normally employed for facilitating the dispersion of activeingredients, recognizing the accepted fact that the formulation and modeof application of a toxicant may affect the activity of the material.The present compounds may be applied, for example, as a spray, dust, orgranule, to the area in which pest control is desired, the choice ofapplication varying of course with the type of pest and the environment.Thus, the compounds of this invention may be formulated as granules oflarge particle size, as powdery dusts, as wettable powders, asemulsifiable concentrates, as solutions, and the like.

Dusts are admixtures of the active ingredients with finely dividedsolids such as talc, attapulgite clay, kieselguhr, pyrophyllite, chalk,diatomaceous earths, calcium phosphates, calcium and magnesiumcarbonates, sulfur, flours, and other organic and inorganic solids whichact as dispersants and carriers for the toxicant. These finely dividedsolids have an average particle size of less than about 50 microns. Atypical dust formulation useful herein contains 10.0 parts of3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate, 30.0parts of bentonite clay, and 60.0 parts of talc.

The compounds of the present invention may be made into liquidconcentrates by solution or emulsion in suitable liquids, and into solidconcentrates by admixtures with talc, clays, and other known solidcarriers used in the pesticide art. The concentrates are compositionscontaining about 5-50% toxicant, and 95-50% inert material whichincludes dispersing agents, emulsifying agents, and wetting agents. Theconcentrates are diluted for practical application, with water or otherliquid for sprays or with additional solid carrier for use as dusts.Typical carriers for solid concentrates (also called wettable powders)include fuller's earth, kaolin clays, silicas, and other highlyabsorbent, readily wet inorganic diluents. A solid concentrateformulation useful herein contains 1.5 parts each of sodiumlignosulfonate and sodium laurylsulfate as wetting agents, 25.0 parts of5-benzyl-3-furylmethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate and 72.0parts of bentonite clay.

Useful liquid concentrates include the emulsifiable concentrates, whichare homogeneous liquid or paste compositions readily dispersed in wateror other dispersant, and may consist entirely of the toxicant with aliquid or solid emulsifying agent, or may also contain a liquid carriersuch as xylene, heavy aromatic naphthas, isophorone and othernonvolatile organic solvents. For application, these concentrates aredispersed in water or other liquid carrier, and normally applied as aspray to the area to be treated.

Typical wetting, dispersing or emulsifying agents used in pesticidalformulations include, for example, the alkyl and alkylaryl sulfonatesand sulfates and their sodium salts; alkylamide sulfonates, includingfatty methyl taurides; alkylaryl polyether alcohols, sulfated higheralcohols, polyvinyl alcohols; polyethylene oxides; sulfonated animal andvegetable oils; sulfonated petroleum oils; fatty acid esters ofpolyhydric alcohols and the ethylene oxide addition products of suchesters; and the addition products of long-chain mercaptans and ethyleneoxide. Many other types of useful surface-active agents are available incommerce. The surface-active agent, when used, normally comprises from1-15% by weight of the pesticidal composition.

Other useful formulations include simple solutions of the activeingredient in a solvent in which it is completely soluble at the desiredconcentration, such as acetone or other organic solvents.

The concentration of the toxicant in the dilution generally used forapplication is normally in the range of about 2% to about 0.001%. Manyvariations of spraying and dusting compositions in the art may be used,by substituting a compound of this invention into compositions known orapparent to the art.

Pesticidal compositions may be formulated and applied with other activeingredients, including other insecticides, nematicides, acaricides,fungicides, plant growth regulators, fertilizers, etc. In applying thechemicals, it is obvious that an effective amount and concentration ofthe compound of the invention should be employed. For agriculturalapplication the active ingredient of the invention may be applied at arate of 75 to 4000 g per hectare, preferably 150 to 3000 g per hectare.

It is apparent that many modifications may be made in the structure,preparation, formulation and application of the compounds of thisinvention, without departing from the spirit and scope of the inventionand of the following claims.

                  Table 1                                                         ______________________________________                                        Initial Toxicity to Insects and Mites                                         Compound                                                                              Conc.   % Kill                                                        of Example                                                                            (PPM)   BB      AW    PA    M      MWB                                ______________________________________                                        2       1250    100     100   100   97     100                                         156    100     100    40   3.6     20                                3       1250    100     100   100   44     100                                         156    100     100    60   8.9     80                                4       1250    100     100    56   100    100                                         156    100     100   100   4.7     90                                ______________________________________                                         BB: Mexican bean beetle                                                       AW: Southern armyworm                                                         PA: Pea aphid                                                                 M: Twospotted spider mite                                                     MWB: Milkweed bug                                                        

                  Table 2                                                         ______________________________________                                        Residual (7-Day) Toxicity to Insects and Mites                                Compound Conc.     % Kill                                                     of Example                                                                             (PPM)     BB     AW   PA   M   MWB   BW                              ______________________________________                                        2        1250      100    100  100  0   10    20                                        312      100     59   89  0   10    20                              3        1250      100     25   17  0    5    15                                        312       75     0    8   0    5    15                              4        1250      100    100  100  0   80    30                                        312      100    100  100  0   60    45                              ______________________________________                                         BB: Mexican bean beetle                                                       AW: Southern armyworm                                                         PA: Pea aphid                                                                 M: Twospotted spider mite                                                     MWB: Milkweed bug                                                             BW Boll weevil                                                           

                                      Table 3                                     __________________________________________________________________________    Comparative Initial Contact Activity                                                 Conc.                                                                              % Kill                                                            Compound                                                                             (PPM)                                                                              BB   AW   PA   M   MWB                                            __________________________________________________________________________    Example 2                                                                            1250 100  100  100(100)                                                                           97  100(100)                                              156  100  100(72)                                                                            40(100)                                                                            3.6 20(80)                                                78    --  --(53)                                                                             --(100)                                                                            --  --(43)                                                39   100(100)                                                                           42(12)                                                                             0    5.1 0                                                     20    --  --(65)                                                                             --   --  --                                                    2.5  100(100)                                                                           0    --   --  --                                             Example 4                                                                            1250 100  100  56   100 100                                                   156  100  100(100)                                                                           100  4.7 90(95)                                                39   95(100)                                                                            100(84)                                                                            100(75)                                                                            5.6 10(10)                                                10   100(62)                                                                            27(0)                                                                              --(25)                                                                             --   5                                                    2.5  89(93)                                                                             17   --   --  --                                             Compound A                                                                           1250 60   0    7    0   35                                                    312  45   0    0    0    0                                                    78   11   0    0    0   10                                                    20   41   0    0    0    0                                             Compound B                                                                           1250 94   0    2    0   20                                                    312  19   0    --   0   20                                                    78   0    0    --   0    5                                             Compound C                                                                           1250 93   6    0    5   15                                                    312  89   0    --   0   25                                                    78   25   0    --   0   0                                              __________________________________________________________________________     Mortality figures in parentheses are from a separate test. See Example 6      for identity of compounds A, B and C.                                    

I claim:
 1. An insecticidal compound of the formula: ##STR3## in which Xis halogen, cyano, nitro, aryl, aralkyl, aryloxy, arylthio, alkyl of C₁-C₄, alkoxy of C₁ -C₄, alkylthio of C₁ -C₄, haloalkyl of C₁ -C₂,dialkylamino in which alkyls are C₁ -C₂, or methylenedioxy; Y is halogenor haloalkyl of C₁ -C₂ ; n is 0, 1, 2, or 3; and R is an alcohol residueselected from the group consisting of:(a) a benzyl- orphenoxy-substituted benzyl group of the formula: ##STR4## wherein Z ishydrogen, methyl, cyano, ethynyl, or phenyl and A is --O-- or --CH₂ --;(b) 5-benzyl-3-furylmethyl; (c) an imidomethyl group selected from thegroup consisting of maleimidomethyl, phthalimidomethyl, andtetrahydrophthalimidomethyl; and (d) a benzyl group substituted in atleast two ring positions with chloro, methyl, or methylenedioxy groups,selected from the group consisting of 3,4-methylenedioxybenzyl,2-chloro-4,5-methylenedioxybenzyl, and 2,4-dimethylbenzyl.
 2. Thecompound of claim 1 in which X is chloro, cyano, methyl, methoxy, ormethylenedioxy; Y is chloro or bromo; and n is 0, 1, or
 2. 3. Thecompound of claim 2 in which Y is chloro and n is
 0. 4. The compound ofclaim 3 in which R is 3-phenoxybenzyl, α-cyano-3-phenoxybenzyl, or5-benzyl-3-furylmethyl.
 5. The compound of claim 4 which is3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate.
 6. Thecompound of claim 4 which is 5-benzyl-3-furylmethyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate.
 7. Thecompound of claim 4 which is α-cyano-3-phenoxybenzyl3-(β-chloro-β-phenylvinyl)-2,2-dimethylcyclopropanecarboxylate.
 8. Aninsecticidal composition comprising an insecticidally effective amountof a compound of claim 1 in admixture with an agriculturally acceptableextender.
 9. An insecticidal composition of claim 8 which contains asurface active agent.
 10. A method of controlling insects whichcomprises applying to the locus where control is desired aninsecticidally effective amount of a compound of claim 1.